Scale deposit inhibitor, process for its production, polymerizer whose inside wall is covered with the inhibitor, and process for production of vinylic polymers by the use of the polymerizer

ABSTRACT

A scale adhesion preventing agent for use in a polymerization reactor, consisting essentially of a condensate of a phenol represented by the following formula (1), a 1-naphthol and an aldehyde, which is soluble in an alkaline aqueous solution:  
                 
 
     wherein R 1  and R 2  are the same or different and each a hydroxyl group, alkyl group having 1 to 8 carbon atoms, halogen atom, hydrogen atom, alkoxycarbonyl group whose alkyl moiety has 1 to 8 carbon atoms or phenyl group, with the proviso that a hydrogen atom is existent at at least two of ortho-positions and para-positions with respect to the hydroxyl group.  
     When a vinyl-based monomer is to be polymerized using a polymerization reactor having a film of this scale adhesion preventing agent on the inner wall, the vinyl-based polymer can be produced by preventing the adhesion of a scale.

FIELD OF THE INVENTION

[0001] The present invention relates to an agent for preventing theadhesion of a scale produced during the polymerization reaction of avinyl monomer such as styrene, vinyl acetate, vinyl chloride,styrene-acrylonitrile or styrene-butadiene by suspension polymerizationor emulsion polymerization to the inner wall of a polymerizationreactor, a production process therefor, a polymerization reactor havingthe agent applied to the inner wall and a process for producing avinyl-based polymer using this polymerization reactor.

[0002] Specifically, it relates to an agent for preventing the adhesionof a scale produced during the production of a vinyl chloride-basedpolymer to the inner wall of a polymerization reactor.

DESCRIPTION OF THE PRIOR ART

[0003] In the production of a polymer by the suspension polymerizationor emulsion polymerization of a vinyl monomer such as styrene or vinylchloride, the polymer of the monomer is adhered to the inner wall of apolymerization reactor, a stirrer, a heat exchanger and other elementsexistent in the polymerization reactor (all of them will be simplyreferred to as “inner wall of a polymerization reactor” hereinafter) asa scale, thereby reducing the heat exchange efficiency, or the scalefalls off from the inner wall and gets mixed in the polymer product,thereby deteriorating the quality of the product. Therefore, to preventthe adhesion of the scale to the inner wall of the polymerizationreactor, a substance for preventing a scale from adhering to the innerwall of the polymerization reactor (scale adhesion preventing agent) iscoated on the inner wall of the polymerization reactor in the form of athin film. As the scale adhesion preventing agent used for this purposeis proposed a condensate of a phenol and an aldehyde (JP-A 62-201832)(the term “JP-A” as used herein means an “unexamined published Japanesepatent application”), a self-condensate of a polyphenol or apolynaphthol (JP-B 62-3841) (the term “JP-B” as used herein means an“examined Japanese patent publication”) and a condensate of 1-naphtholand formaldehyde (JP-B 1-31523). However, these scale adhesionpreventing agents are unsatisfactory in terms of adhesion preventingeffect or cannot retain their adhesion preventing effect for a long timethough they have an adhesion preventing effect. Therefore, they cannotbe used for a plurality of polymerization operations.

[0004] Further, a condensate of an aldehyde, phenol compound andaromatic carboxylic acid having a hydroxyl group introduced into thearomatic nucleus (W098/24820) is proposed as a scale adhesion preventingagent which can retain its scale adhesion preventing effect for a longertime than the above scale adhesion preventing agents. However, the scaleadhesion preventing agent which contains a relatively strong acid groupsuch as sulfonic acid group or carboxylic acid group, or a basic groupsuch as amino group or imino group has a relatively large influence uponthe color of a molded product of a vinyl-based polymer.

[0005] That is, conventionally proposed scale adhesion preventing agentshave various problems, which their scale adhesion preventing effect isunsatisfactory, which the effect cannot be retained for a long time, andwhich they fall off from the inner wall of a polymerization reactor andget mixed in a product polymer, thereby deteriorating the quality of theproduct. Consequently, the development of a more preferred scaleadhesion preventing agent is desired.

OBJECT OF THE INVENTION

[0006] It is an object of the present invention to provide a novel scaleadhesion preventing agent for preventing the adhesion of a scale to apolymerization reactor during the suspension polymerization or emulsionpolymerization of a vinyl-based monomer.

[0007] It is another object of the present invention to provide a scaleadhesion preventing agent which can retain its large scale adhesionpreventing effect for a long time during the suspension polymerizationor emulsion polymerization of a vinyl-based monomer.

[0008] It is still another object of the present invention to provide aprocess for producing the scale adhesion preventing agent of the presentinvention.

[0009] It is a further object of the present invention to provide apolymerization reactor having a film of the above scale adhesionpreventing agent on the inner wall.

[0010] It is a still further object of the present invention to providea process for producing a vinyl-based polymer using a polymerizationreactor having a film of the above scale adhesion preventing agent onthe inner wall.

[0011] Other objects and advantages of the present invention will becomeapparent from the following description.

SUMMARY OF THE INVENTION

[0012] The inventors of the present invention have conducted variousstudies to attain the above objects and have found that when acondensation product soluble in an alkaline aqueous solution, which isobtained by a condensation reaction among a phenol, a 1-naphthol and analdehyde, is applied to the inner wall of a polymerization reactorbefore the suspension polymerization or emulsion polymerization of avinyl-based monomer, particularly a vinyl chloride monomer, it producesan excellent scale adhesion preventing effect, hardly exerts a badinfluence upon the color of a molded product of the obtained vinyl-basedpolymer and hardly causes a fish eye in the polymer. The presentinvention has been accomplished based on this finding.

[0013] That is, the present invention is a scale adhesion preventingagent consisting essentially of a condensate of a phenol represented bythe following formula (1) (to be simply referred to as “phenol”hereinafter), a 1-naphthol and an aldehyde, which is soluble in analkaline aqueous solution:

[0014] wherein R¹ and R² are the same or different and each a hydroxylgroup, alkyl group having 1 to 8 carbon atoms, halogen atom, hydrogenatom, alkoxycarbonyl group whose alkyl moiety has 1 to 8 carbon atoms orphenyl group, with the proviso that a hydrogen atom is existent at atleast two of ortho-positions and para-positions with respect to thehydroxyl group.

[0015] In the present invention, it is important that the above phenolshould not have a strong acid group such as sulfonic acid group orcarboxylic acid group, or a base such as amino group or ammonium group.That is, when a phenol having the above substituent is used, it producesan unfavorable effect such as coloration on a vinyl-based polymer,particularly a vinyl chloride-based polymer.

[0016] The phenol used in the present invention is preferably a compoundselected from the group consisting of monophenols such as phenol,o-cresol, p-cresol, p-t-butylphenol, o-t-butylphenol, m-chlorophenol andmethyl salicylate; diphenols such as catechol, resorcinol,2-methylresorcinol and hydroquinone; triphenols such as pyrogallol,phloroglucinol and hydroxyhydroquinone; and biphenyls such aso-hydroxybiphenyl, p-hydroxybiphenol and 2,4-dihydroxybiphenyl, or amixture of two or more thereof. Out of these, a diphenol or triphenolcan be advantageously used because they have an excellent scale adhesionpreventing effect. Out of these, catechol is particularly preferred.

[0017] The 1-naphthol which can be advantageously used in the presentinvention is a compound represented by the following formula (2):

[0018] wherein m is 0 or 1 to 3, and n is 0 or 1.

[0019] Examples of the 1-naphthol include dihydroxynaphthalenes such as1-naphthol, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene,1,6-dihydroxynaphthalene and 1,8-dihydroxynaphthalene;trihydroxynaphthalenes such as 1,3,5-trihydroxynaphthalene,1,3,6-trihydroxynaphthalene and 1,5,7-trihydroxynaphthalene; andtetrahydroxynaphthalenes such as 1,5,7,8-tetrahydroxynaphthalene.

[0020] These compounds may be used alone or as a mixture of two or more.The 1-naphthol may have a substituent other than a group which isdissociated in water as an ion, such as alkyl group or halogen atom, ata position other than the 2-position and 4-position of a nucleus.

[0021] The 1-naphthol is preferably 1-naphthol.

[0022] The aldehyde advantageously used in the present invention isformaldehyde, acetaldehyde, propionaldehyde, benzaldehyde or furfural.Scale adhesion preventing agents obtained by using formaldehyde andacetaldehyde have excellent adhesion preventing capability and canachieve high compatibility with a vinyl-based polymer, particularly avinyl chloride-based polymer by suitably selecting the amounts of aphenol and a 1-naphthol to be condensed therewith. Therefore, even whenthe film of the scale adhesion preventing agent falls off from the innerwall of a polymerization reactor and gets mixed in a product polymerduring the polymerization of a vinyl-based monomer, it hardly becomesthe cause of the coloration of the polymer or a noncompatible foreignsubstance. Out of these, formaldehyde is particularly preferred becauseit retains a scale adhesion prevention effect for a long time. In thiscase, formaldehyde or acetaldehyde may be used alone or in combinationwith another aldehyde. When it is used in combination with anotheraldehyde, formaldehyde or acetaldehyde is used in an amount ofpreferably 10 mol % or more, more preferably 40 mol % or more based onthe total of all aldehydes.

[0023] When benzaldehyde is used as the aldehyde in the presentinvention, a scale adhesion preventing agent which can retain its effectfor a long time can be obtained. Therefore, in order to obtain a scaleadhesion preventing agent which can retain its effect for a long time,benzaldehyde is preferably used. When benzaldehyde is used, it is usedin an amount of preferably 10 mol % or more, more preferably 70 mol % ormore based on the total of all aldehydes. Otherwise, a satisfactoryeffect is hardly obtained.

[0024] The present invention is a scale adhesion preventing agent whichconsists essentially of a co-condensate of the above phenol, 1-naphtholand aldehyde and totally differs from a condensate of a phenol and analdehyde and/or a condensate of a 1-naphthol and an aldehyde. That is,when a condensate of a phenol and an aldehyde and a condensate of a1-naphthol and an aldehyde are mixed together, the scale adhesionpreventing effect of the resulting mixture is small, or the amount of acolored foreign substance contained in a molded product of a vinyl-basedpolymer increases.

[0025] In the present invention, the ratio of the above phenol,1-naphthol and aldehyde is not particularly limited but the phenol isused in an amount of preferably 0.01 to 2 mols, more preferably 0.3 to0.8 mol based on 1 mol of the 1-naphthol. That is, when the amount ofthe phenol is smaller than 0.01 mol, the amount of a colored foreignsubstance contained in the vinyl-based polymer or the number of fisheyes tends to increase. When the amount of the phenol is larger than 2mols, the scale adhesion preventing effect tends to decrease.

[0026] The amount of the aldehyde is generally 0.2 mol or more,preferably 0.5 to 2 mols, more preferably 0.6 to 1.2 mols based on 1 molof the total of the phenol and 1-naphthol. That is, when the amount ofthe aldehyde is larger than 2 mols, a crosslinking reaction between thephenol and the 1-naphthol proceeds, whereby a condensate insoluble in analkaline aqueous solution is readily formed. When the amount of thealdehyde is smaller than 0.2 mol, a condensation reaction hardlyproceeds completely, whereby the scale adhesion preventing effect tendsto decrease.

[0027] One of particularly preferred embodiments of the presentinvention is a scale adhesion preventing agent obtained by co-condensinga diphenol or triphenol, particularly catechol as the phenol, 1-naphtholas the 1-naphthol and formaldehyde or acetaldehyde as the aldehyde inthe above ratio. This scale adhesion preventing agent has a large scaleadhesion preventing effect and extremely high compatibility with avinyl-based polymer. A colored foreign substance or fish eye is rarelyseen in a molded product of a vinyl polymer obtained by polymerizationusing a polymerization reactor having a film of this scale adhesionpreventing agent on the inner wall.

[0028] In the present invention, the method of carrying out acondensation reaction among a phenol, 1-naphthol and aldehyde is notparticularly limited. Conventional means of obtaining a precursor of aphenol resin, such as resol, resitol or novolak is used. For instance,when a solvent is used, water, an organic solvent or a mixture thereofis used and when a catalyst is used, a basic catalyst such as sodiumhydroxide or potassium hydroxide, or an acidic catalyst such ashydrochloric acid, phosphoric acid, acetic acid or oxalic acid is used.

[0029] The condensation reaction temperature is preferably from roomtemperature (25° C.) to 300° C., more preferably from 30 to 150° C.Particularly when the total process of the condensation reaction iscarried out at substantially a constant temperature, a temperature rangeof 50 to 95° C. is used. The condensation reaction time is notparticularly limited but preferably 2 minutes to 72 hours, morepreferably 2 to 12 hours.

[0030] The condensation reaction product formed by the condensationreaction of the present invention is a mixture of condensates whichdiffer from one another in raw material ratio and the degree ofcondensation, which may contain unreacted raw materials and is solublein an alkaline aqueous solution. The reaction mixture may be used as ascale adhesion preventing agent directly or after impurities such as anunreacted product are removed by purification and further the solvent isremoved or reduced by distillation or the like, or the solvent is addedto dilute the mixture as required.

[0031] Although the scale adhesion preventing agent of the presentinvention can be prepared as a solid by completely removing the solvent,it is provided as a solution (or suspension) having a concentration ofpreferably 50 wt % or less, more preferably 0.2 to 10 wt %.

[0032] In the particularly preferred condensation method in the presentinvention, a phenol, 1-naphthol and aldehyde are mixed together in anaqueous solvent in the presence of a basic catalyst such as sodiumhydroxide, potassium hydroxide or ammonia at 80° C. or less, thetemperature of the mixture is elevated slowly to preferably 90 to 150°C., more preferably 95 to 110° C. at a rate of preferably 2° C./min orless, more preferably 1° C./min or less, and optionally a reaction iscontinued at the above temperature range for preferably 2 minutes to 72hours, more preferably 1 to 10 hours, much more preferably 3 to 8 hours.

[0033] That is, the condensation reaction is caused to proceed mildly ata relatively low temperature in the initial stage and completed at arelatively high temperature in the end so that at the time of its use,that is, when the obtained scale adhesion preventing agent is applied tothe inner wall of a polymerization reactor for a vinyl-based monomer,the formed film has high uniformity, high adhesion to the inner wall,particularly stainless steel inner wall of a polymerization reactor anda large scale adhesion preventing effect and can retain this effect fora long time.

[0034] When the condensation reaction is carried out at a hightemperature from the initial stage of condensation or by rapidlyincreasing the temperature, the condensation reaction proceeds rapidly,thereby forming a heterogeneous condensate. When this heterogeneouscondensate is used as a scale adhesion preventing agent, the amount of acolored foreign substance contained in the vinyl-based polymer tends toincrease.

[0035] However, when the condensation reaction is carried out at a toolow temperature, it proceeds too slowly. Therefore, it is preferred tomix together a phenol, 1-naphthol and aldehyde at a temperature ofpreferably 50 to 80° C., more preferably 65 to 75° C. and carry out areaction at an increased temperature from industrial view.

[0036] When the condensation reaction is not completed at a temperatureof 90° C. or more, the condensation reaction does not proceed completelyand when the obtained condensation product is used as a scale adhesionpreventing agent, its scale adhesion preventing effect is low. When thecondensation reaction is completed at a high temperature, for example,150° C., particularly more than 300° C., the obtained scale adhesionpreventing agent tends to cause a colored foreign substance and a largenumber of fish eyes in the vinyl-based polymer.

[0037] To produce the scale adhesion preventing agent of the presentinvention, the order of mixing components to be subjected to thecondensation reaction is not particularly limited but it is recommendedto add a phenol, 1-naphthol and basic catalyst to an aqueous solvent andthen add an aldehyde to the resulting solution gradually.

[0038] As the aqueous solvent is generally used water alone. However, toshorten the drying time after the application of the obtained scaleadhesion preventing agent, an organic solvent having compatibility withwater, such as methanol or ethanol, may be used in an amount of 30 wt %or less in limits that do not deteriorate the dispersibility (orsolubility) of the condensation product. After the completion of thecondensation reaction, the reaction product is used as a scale adhesionpreventing agent directly or after it is purified and furtherconcentrated or diluted as described above. Since the condensationreaction product is soluble in an alkaline aqueous solution, it ispreferably prepared as an aqueous solution having a pH of 8 to 13.5.

[0039] Other substances may be further added to the scale adhesionpreventing agent of the present invention in limits that do not preventthe scale adhesion preventing effect of the agent. The substancesinclude a water-soluble polymer compound such as polyvinyl alcohol,partly saponified polyvinyl alcohol, methyl cellulose or sodiumpolyacrylate; anionic surfactant such as sodium dodecylsulfate;water-dispersible fine particles such as silica sol or alumina sol; andwater-soluble alkali metal salt such as sodium carbonate, sodiumsilicate, sodium ascorbate, sodium citrate, sodium hydrogensulfite,sodium dithionite, sodium pyrophosphate, sodium hydrogenphosphate orpotassium acetate.

[0040] The total amount of the above additives is preferably 30 wt % orless based on the condensate.

[0041] The scale adhesion preventing agent of the present invention canbe applied to a polymerization reactor for the suspension polymerizationor emulsion polymerization of a vinyl-based monomer.

[0042] The vinyl-based monomer is a vinyl monomer such as styrene, vinylchloride, vinyl acetate or methyl (meth) acrylate, a mixture of two ormore thereof, or a mixture thereof with another monomer copolymerizablewith the above monomer or monomer mixture, such as vinylidene chloride,acrylonitrile, ethylene or butadiene. In the present invention, a vinylchloride-based monomer, that is, vinyl chloride or a mixture of vinylchloride and another monomer copolymerizable with vinyl chloride, suchas vinyl acetate, ethylene, vinyliden chloride or acrylonitrile isparticularly preferred.

[0043] The structure, material and the like of a polymerization reactorto be coated with the scale adhesion preventing agent of the presentinvention are not particularly limited. A known polymerization reactoris used. Examples of the polymerization reactor include metalpolymerization reactors such as a stainless steel polymerizationreactor, polymerization reactors lined with glass and glasspolymerization reactors, including a stirrer, baffle and reflux coolerattached thereto.

[0044] The scale adhesion preventing agent of the present invention isapplied to the inner wall of a polymerization reactor as uniformly aspossible.

[0045] The application technique is not particularly limited but thescale adhesion preventing agent may be coated or sprayed. In the case ofcoating, a solution containing 0.2 to 10 wt % of the scale adhesionpreventing agent is preferably applied by a brush or other similarcoating tool, or caused to flow down over the inner wall of thepolymerization reactor. In the case of spraying, a solution containing0.2 to 10 wt % of the scale adhesion preventing agent is sprayed by aspray tool such as an ejector. The drive gas used for this purpose maybe nitrogen or air and not particularly limited but steam is preferred.By using steam, the scale adhesion preventing agent to be sprayed isdiluted to 10 to 1,000 times, thereby making it possible to formuniformly a thin film advantageously.

[0046] The scale adhesion preventing agent is applied to the inner wallof the polymerization reactor and dried to form a strong film. An excessof the scale adhesion preventing agent is removed by rinsing with wateras required.

[0047] Therefore, according to the present invention, there is alsoprovided a polymerization reactor which has a film of a scale adhesionpreventing agent consisting essentially of a condensate obtained bycondensing a phenol, a 1-naphthol and an aldehyde on the inner wall toproduce a corresponding vinyl-based polymer by polymerizing avinyl-based monomer, particularly a vinyl-based polymer by polymerizinga vinyl chloride-based monomer.

[0048] The thickness of the film of the condensate formed on the innerwall of the above polymerization reactor is not particularly limited butpreferably 0.001 to 10 g/m² as the weight of the condensate.

[0049] According to the present invention, there is further provided aprocess for producing a vinyl-based polymer, comprising the step ofcarrying out the suspension polymerization or emulsion polymerization ofa vinyl-based monomer using a polymerization reactor having a film of acondensate of a phenol, a 1-naphthol and an aldehyde on the inner wall.In this case, any known polymerization method may be used. That is, aknown reaction initiator such as an organic peroxide exemplified byisopropyl peroxydicarbonate, lauroyl peroxide, tertiary butylperoxypyvarate and benzoyl peroxide, an inorganic peroxide exemplifiedby potassium persulfate or azo-based compound exemplified byazobisbutyronitrile is used as a polymerization initiator. A redoxcatalyst which is a combination of a peroxide and a reducing agent isoptionally used.

[0050] A dispersion stabilizer is generally used in suspensionpolymerization. Examples of the dispersion stabilizer include partlysaponified polyvinyl alcohols and methyl celluloses.

[0051] An emulsion stabilizer is generally used in emulsionpolymerization. Examples of the emulsion stabilizer include anionicsurfactants such as sodium dodecylsulfate and nonionic surfactants suchas polyoxyethylene lauryl ether.

[0052] Further, in polymerization of a vinyl chloride-based monomer, themolecular weight of the polymer may be optionally adjusted by using amercapto-based compound such as ethyl mercaptan or a chlorine compoundsuch as carbon tetrachloride as a chain transfer agent.

EXAMPLES

[0053] The following examples are provided for the purpose of furtherillustrating the present invention but are in no way to be taken aslimiting.

[0054] In Examples, tests were carried out in accordance with thefollowing methods.

(1) Scale Adhesion Prevention Properties

[0055] The suspension polymerization and emulsion polymerization ofvinyl chloride were carried out and evaluated.

[0056] (Suspension Polymerization)

[0057] 28 kg of ion exchange water, 485 g of a 4 wt % aqueous solutionof partly saponified polyvinyl alcohol (KH-20 of Nippon Gosei Co.,Ltd.), 5.1 g of tertiary butyl peroxyneodecanoate as a radical initiator(KS-23 of Kayaku Akuzo Co., Ltd.) and 6.1 g of tertiary butylperoxypyvarate (PS—N of NOF Corporation) were fed to a polymerizationreactor (inner wall made from stainless steel) and then 18.65 kg ofvinyl chloride monomer was fed to the reactor. Polymerization wascarried out at 63.50° C. under agitation with three blue margin bladesat 700 rpm for about 4 hours. After polymerization, a polymer and awater medium were taken out and the reactor was washed with watersoftly.

[0058] This operation was considered as one batch and the next chargewas then fed to the reactor to carry out polymerization continuously.After three batches, a scale adhered to the inner wall (20 cm×20 cm)near the gas-liquid interface was collected with a bronze spatula andvacuum dried at 40° C. for 12 hours, and the weight of the scale wasshown as the deposition A (g/m²) of the scale. Subsequently, the nextcharge was fed to the reactor by the above operation, and a scale after5 batches was collected by the above method and shown as the depositionB (g/m²) of the scale.

[0059] (Emulsion Polymerization)

[0060] 25 kg of ion exchange water, 75 g of sodium lauryl sulfate and 4g of potassium persulfate were fed to a polymerization reactor (innerwall made from stainless steel) and then 12 kg of vinyl chloride monomerwas fed to the reactor. Emulsion polymerization was carried out at 70°C. under agitation with Faudora blades at 900 rpm for 8 hours. Afterpolymerization, a polymer and a water medium were taken out and thereactor was washed with water softly.

[0061] This operation was considered as one batch and the next chargewas then fed to the reactor to carry out polymerization continuously.After three batches, a scale adhered to the inner wall (20 cm×20 cm)near the gas-liquid interface was collected with a bronze spatula andvacuum dried at 40° C. for 12 hours, and the weight of the scale wasshown as the deposition C (g/m²) of the scale. Subsequently, the nextcharge was fed to the reactor by the above operation, and a scale afterfive batches was collected by the above method and shown as thedeposition D (g/m²) of the scale.

(2) Coloration of Molded Product of Vinyl Chloride-Based Polymer

[0062] 2 parts by weight of tribasic lead sulfate, 1.5 parts by weightof zinc stearate, 0.5 part by weight of calcium stearate and 0.2 part byweight of stearic acid were mixed with 100 parts by weight of the abovepolyvinyl chloride obtained by suspension polymerization by theplastomill of Toyo Seiki Co., Ltd. at 185° C. for 15 minutes, and theresulting mixture was thermally pressed at 175° C. for 10 minutes toobtain a 5 mm-thick sheet. The brightness index (L value) of the sheetwas measured by the Z-Σ80 color difference meter of Nippon DenshokuKogyo Co., Ltd. The larger the L value the higher the whiteness becomes(excellent in coloration resistance).

(3) Colored Foreign Substance Contained in Molded Product of VinylChloride-Based Polymer

[0063] 4 parts by weight of dibutyltin maleate was added to 100 parts byweight of the above polyvinyl chloride obtained by suspensionpolymerization and the resulting mixture was molded from the T die of a20 mm-diameter single-screw extruder (185° C.) to form a sheet having awidth of about 70 mm and a thickness of about 0.2 mm. The number ofcolored foreign substances contained in 100 m of this sheet was countedvisually.

[0064] Reference symbols in the columns of 1-naphthol, phenol andaldehyde in Table 1 and Table 4 represent the following compounds.

[0065] A1: 1-naphthol, A2: 1,6-dihydroxynaphthalene, A3:1,3-dihydroxynaphthalene, B1: pyrogallol, B2: catechol, B3: resorcinol,B4: 2-methylresorcinol, B5: p-butylphenol, B6: carbolic acid, B7:o-hydroxybiphenyl, B8: o-cresol, B9: hydroquinone, B10: m-chlorophenol,B11: 2-hydroxybenzoic acid, B12: p-aminophenol, C1: 37 wt %formaldehyde, C2: 90 wt % acetaldehyde, C3: benzaldehyde, Na: sodiumhydroxide, K: potassium hydroxide, HCl: 36% hydrochloric acid, P:phosphoric acid

Example 1

[0066] 25 g of 1-naphthol, 10 g of pyrogallol, 7 g of sodium hydroxideand 300 g of distilled water were fed to a 500 ml closed glass vesselequipped with a cooling capacitor. After the inside of the vessel wassubstituted by nitrogen, the resulting mixture was heated at 70° C. in ahot bath under agitation. Thereafter, 20 g of a 37 wt % aqueous solutionof formaldehyde was added slowly under agitation. A condensationreaction was carried out under agitation for 5 hours by maintaining thattemperature. A yellowish transparent aqueous solution was obtained.

[0067] An alkaline aqueous solution of the above condensation productwas adjusted to a concentration of 0.5 wt % and applied to the innerwall (stainless steel) of a reactor for polymerizing vinyl chloridehaving an inner capacity of about 50 liters by a steam ejector spray.

[0068] Thereafter, the reactor was washed with water to obtain apolymerization reactor having a film formed on the inner wall. Thethickness of the formed film estimated from the difference between theweight of the condensate input into the polymerization reactor and theweight of the condensate output as waste water was about 0.2 g/m².

[0069] A scale adhesion prevention test was made on the obtainedpolymerization reactor, and coloration and colored foreign substancetests were made on a molded product of the obtained vinyl chloride-basedpolymer.

[0070] According to the results of the above tests, the deposition A ofthe scale adhesion preventing agent was 3 g/m², the deposition B was 10g/m², the deposition C was 5 g/m², the deposition D was 14 g/m², thebrightness index was L=73 and the number of colored foreign substanceswas 2. The conditions for producing the scale adhesion preventing agentare shown in Table 1 and Table 2 and the results obtained by using thescale adhesion preventing agent are shown in Table 3.

Examples 2 to 16

[0071] Polymerization reactors having a film formed on the inner wallwere obtained in the same manner as in Example 1 except that the typesand amounts of the 1-naphthol, phenol and aldehyde were changed as shownin Table 1 and the condensation conditions were changed as shown inTable 2. The weights of the formed films are shown in Table 2. A scaleadhesion prevention test was made on the obtained polymerizationreactors, and coloration and colored foreign substance tests were madeon molded products of the obtained vinyl chloride-based polymers. Theresults of the above tests are shown in Table 3.

[0072] Since a condensate obtained by using an acid catalyst is solid,it was dissolved in an alkali aqueous solution before use. TABLE 11-naphthol phenol aldehyde distilled molar molar molar catalyst watertype g ratio type g ratio¹⁾ type g ratio²⁾ type g g Ex. 1 A1 25 1 B1 100.46 C1 20 0.98 Na 7 300 Ex. 2 A1 25 1 B2 10 0.52 C1 13 0.61 Na 7 300Ex. 3 A1 25 1 B3 5 0.26 C1 18 1.02 Na 7 300 Ex. 4 A1 25 1 B4 2 0.09 C116 1.04 Na 8 300 Ex. 5 A2 25 1 B5 9 0.38 C1 14 0.80 Na 9 300 Ex. 6 A1 211 B6 7 0.56 C1 16 0.96 K 12 300 Ex. 7 A1 25 1 B7 9 0.31 C1 15 0.82 K 10300 Ex. 8 A1 25 1 B8 5 0.27 C1 20 0.98 Na 7 300 B5 5 0.19 Ex. 9 A1 25 1B3 9 0.47 C1 20 0.97 HCL 50 300 Ex. 10 A1 25 1 B3 9 0.47 C1 20 0.97 P 50300 Ex. 11 A3 25 1 B1 9 0.46 C1 8 0.43 Na 9 300 C3 12 0.50 Ex. 12 A1 221 B4 3 0.16 C1 8 0.56 Na 7 300 C2 5 0.58 Ex. 13 A1 22 1 B8 5 0.34 C1 80.50 Na 7 300 C2 5 0.51 Ex. 14 A1 25 1 B1 5 0.23 C2 8 0.77 Na 7 300 Ex.15 A1 22 1 B3 8 0.48 C2 9 0.82 Na 7 300 Ex. 16 A1 22 1 B4 5 0.26 C2 101.06 HCL 50 300

[0073] TABLE 2 weight of film temper- (polymerization Initial finalature reaction reac- reactor used for temper- temper- elevation temper-tion suspension ature ature rate ature time polymerization) ° C. ° C. °C./min ° C. Hr g/m² Ex. 1 — — — 70 5 0.2 Ex. 2 — — — 75 5 0.1 Ex. 3 — —— 70 6 0.1 Ex. 4 — — — 70 5 0.1 Ex. 5 — — — 75 5 0.1 Ex. 6 — — — 70 50.1 Ex. 7 — — — 75 5 0.1 Ex. 8 — — — 75 7 0.2 Ex. 9 — — — 75 5 0.2 Ex.10 — — — 75 7 0.3 Ex. 11 — — — 75 6 0.1 Ex. 12 — — — 75 5 0.1 Ex. 13 — —— 75 5 0.1 Ex. 14 — — — 75 5 0.2 Ex. 15 — — — 75 5 0.2 Ex. 16 — — — 75 60.2

[0074] TABLE 3 Test results Scale adhesion prevention (g/m²) number ofdeposi- deposi- deposi- deposi- brightness colored tion tion tion tionindex foreign A B C D (L value) substances Ex. 1 3 10 5 14 73 2 Ex. 2 18 2 12 73 0 Ex. 3 1 8 2 15 73 2 Ex. 4 1 8 4 12 73 3 Ex. 5 3 13 3 15 73 4Ex. 6 4 14 5 15 73 2 Ex. 7 3 11 4 12 73 3 Ex. 8 2 9 5 10 73 5 Ex. 9 1 137 14 73 3 Ex. 10 1 15 7 16 73 2 Ex. 11 3 10 6 14 73 2 Ex. 12 2 8 5 11 731 Ex. 13 4 9 5 10 73 1 Ex. 14 2 10 6 13 73 0 Ex. 15 2 14 5 15 73 0 Ex.16 2 8 7 10 73 0

Example 17

[0075] 25 g of 1-naphthol, 10 g of catechol, 7 g of sodium hydroxide and300 g of distilled water were fed to a 500 ml closed pressure vesselequipped with a cooling capacitor. The inside of the vessel wassubstituted by nitrogen gas and then heated at 70° C. in a hot bathunder agitation. Thereafter, 13 g of a 37 wt % aqueous solution offormaldehyde was added slowly under agitation while that temperature wasmaintained.

[0076] The temperature of the reaction solution was then elevated to100° C. at a rate of 0.7° C./min under agitation and a condensationreaction was carried out at that temperature under agitation for 5hours. As a result, a yellowish transparent aqueous solution of a scaleadhesion preventing agent was obtained.

[0077] The alkaline aqueous solution containing the above condensationproduct was adjusted to a concentration of 0.5 wt % and applied to theinner wall (stainless steel) of a reactor for polymerizing vinylchloride having an inner capacity of 50 liters by a steam ejector spray.Thereafter, the reactor was washed with water to obtain a polymerizationreactor having a film formed on the inner wall.

[0078] The weight of the formed film estimated from the differencebetween the weight of the condensate input into the polymerizationreactor and the weight of the condensate output as waste water was about0.1 g/m².

[0079] A scale adhesion prevention test was made on the obtainedpolymerization reactor, and coloration and colored foreign substancetests were made on a molded product of the obtained vinyl chloride-basedpolymer.

[0080] According to the results of the above tests, the deposition A ofthe scale adhesion preventing agent was 1 g/m², the deposition B was 2g/m², the deposition C was 1 g/m², the deposition D was 3 g/m², thecoloration was L=73 and the number of colored foreign substances was 0.The conditions for producing the scale adhesion preventing agent areshown in Table 4 and Table 5 and the results obtained by using the scaleadhesion preventing agent are shown in Table 6.

Examples 18 to 23

[0081] Condensates and polymerization reactors having a film formed onthe inner wall were obtained by using the same types and amounts of the1-naphthol, phenol and aldehyde as in Example 17 in the same manner asin Example 17 except that condensation conditions were changed as shownin Table 5. The weights of the formed films are shown in Table 5.

[0082] A scale adhesion prevention test was made on the obtainedpolymerization reactors, and coloration and colored foreign substancetests were made on molded products of the obtained vinyl chloride-basedpolymers.

[0083] The results of the above tests are shown in Table 6.

Examples 24 to 38

[0084] Condensates and polymerization reactors having a film formed onthe inner wall were obtained in the same manner as in Example 17 exceptthat the types and amounts of the 1-naphthol, phenol and aldehyde werechanged as shown in Table 4. The weights of the formed films are shownin Table 5.

[0085] A scale adhesion prevention test was made on the obtainedpolymerization reactors, and coloration and colored foreign substancetests were made on molded products of the obtained vinyl chloride-basedpolymers.

[0086] The results of the above tests are shown in Table 6.

Comparative Example 1

[0087] A polymerization reactor having a film formed on the inner wallwas obtained in the same manner as in Example 1 except that the phenolwas not added and the amounts of 1-naphthol and formaldehyde werechanged as shown in Table 4. The weight of the formed film is shown inTable 5. A scale adhesion prevention test was made on the obtainedpolymerization reactor, and coloration and colored foreign substancetests were made on a molded product of the obtained vinyl chloride-basedpolymer. The results of the above tests are shown in Table 6.

Comparative Example 2

[0088] A polymerization reactor having a film formed on the inner wallwas obtained in the same manner as in Example 1 except that2-hydroxybenzoic acid was used as the phenol. The weight of the formedfilm is shown in Table 5. A scale adhesion prevention test was made onthe obtained polymerization reactor, and coloration and colored foreignsubstance tests were made on a molded product of the obtained vinylchloride-based polymer. The results of the above tests are shown inTable 6.

Example 39

[0089] 25 g of 1-naphthol, 10 g of catechol, 7 g of sodium hydroxide and300 g of distilled water were fed to a 500 ml closed pressure vesselequipped with a cooling capacitor. The inside of the vessel wassubstituted by nitrogen gas and then heated at 100° C. in a hot bathunder agitation. Thereafter, 13 g of a 37 wt % aqueous solution offormaldehyde was added slowly under agitation while that temperature wasmaintained. A condensation reaction was carried out at that temperatureunder agitation for 5 hours.

[0090] As a result, a yellowish transparent aqueous solution of a scaleadhesion preventing agent was obtained. An alkaline aqueous solutioncontaining the above condensation product was adjusted to aconcentration of 0.5 wt % and applied to the inner wall (stainlesssteel) of a reactor for polymerizing vinyl chloride having an innercapacity of about 50 liters by a steam ejector spray. Thereafter, thereactor was washed with water to obtain a polymerization reactor havinga film formed on the inner wall. The weigh of the formed film is shownin Table 5. A scale adhesion prevention test was made on the obtainedpolymerization reactor, and coloration and colored foreign substancetests were made on a molded product of the obtained vinyl chloride-basedpolymer. The results of the above tests are shown in Table 6.

Example 40

[0091] A polymerization reactor having a film formed on the inner wallwas obtained in the same manner as in Example 17 except thatcondensation conditions were changed as shown in Table 5. The weight ofthe formed film is shown in Table 5.

[0092] A scale adhesion prevention test was made on the obtainedpolymerization reactor, and coloration and colored foreign substancetests were made on a molded product of the obtained vinyl chloride-basedpolymer. The results of the above tests are shown in Table 6.

Comparative Example 3

[0093] A polymerization reactor having a film formed on the inner wallwas obtained in the same manner as in Example 17 except thatp-aminophenol was used as the phenol. The amount of the formed film isshown in Table 5. A scale adhesion prevention test was made on theobtained polymerization reactor, and coloration and colored foreignsubstance tests were made on a molded product of the obtained vinylchloride-based polymer. The results of the above tests are shown inTable 6. TABLE 4 1-naphthol phenol aldehyde distilled molar molar molarcatalyst water type g ratio type g ratio¹⁾ type g ratio²⁾ type g g Ex.17 A1 25 1 B2 10 0.52 C1 13 0.61 Na 7 300 Ex. 18 A1 25 1 B2 10 0.52 C113 0.61 Na 7 300 Ex. 19 A1 25 1 B2 10 0.52 C1 13 0.61 Na 7 300 Ex. 20 A125 1 B2 10 0.52 C1 13 0.61 Na 7 300 Ex. 21 A1 25 1 B2 10 0.52 C1 13 0.61Na 7 300 Ex. 22 A1 25 1 B2 10 0.52 C1 13 0.61 Na 7 300 Ex. 23 A1 25 1 B210 0.52 C1 13 0.61 Na 7 300 Ex. 24 A1 25 1 B2 6 0.31 C1 13 0.7 Na 7 300Ex. 25 A1 25 1 B2 15 0.79 C1 25 0.99 Na 7 300 Ex. 26 A1 25 1 B2 2 0.10C1 10 0.65 Na 7 300 Ex. 27 A1 25 1 B2 0.5 0.03 C1 9 0.62 Na 7 300 Ex. 28A2 25 1 B2 10 0.58 C2 7 0.58 Na 7 300 Ex. 29 A3 25 1 B2 10 0.58 C3 150.57 Na 7 300 Ex. 30 A1 25 1 B2 10 0.52 C2 7 0.54 Na 7 300 Ex. 31 A1 221 B3 8 0.48 C2 9 0.81 Na 7 300 Ex. 32 A1 25 1 B9 10 0.52 C1 7 0.33 Na 7300 Ex. 33 A1 25 1 B1 10 0.46 C1 20 0.97 Na 6 300 Ex. 34 A1 25 1 B8 100.53 C1 13 0.60 Na 7 300 Ex. 35 A1 25 1 B5 10 0.38 C1 13 0.67 Na 7 300Ex. 36 A1 25 1 B7 10 0.34 C1 13 0.69 Na 7 300 Ex. 37 A1 25 1 B4 10 0.47C1 13 0.64 Na 7 300 Ex. 38 A1 25 1 B10 10 0.45 C1 13 0.64 Na 7 300 C.Ex. 1 A1 31 1 — — — C1 17 0.98 Na 7 300 C. Ex. 2 A1 25 1 B11 10 0.42 C120 1.00 Na 7 300 Ex. 39 A1 25 1 B2 10 0.52 C1 13 0.61 Na 7 300 Ex. 40 A125 1 B2 10 0.52 C1 13 0.61 Na 7 300 C. Ex. 3 A1 25 1 B12 10 0.52 C1 130.61 Na 7 300

[0094] weight of film temper- (polymerization Initial final aturereaction reac- reactor used for temper- temper- elevation temper- tionsuspension ature ature rate ature time polymerization) ° C. ° C. °C./min ° C. Hr g/m² Ex. 17 70 100 0.7 100 5 0.1 Ex. 18 66 108 0.9 108 50.1 Ex. 19 74 100 0.3 100 5 0.1 Ex. 20 61 100 0.7 100 5 0.1 Ex. 21 70115 0.7 115 5 0.1 Ex. 22 50 100 0.7 100 5 0.2 Ex. 23 78 145 0.5 145 50.1 Ex. 24 70 100 0.7 100 5 0.1 Ex. 25 70 100 0.7 100 5 0.1 Ex. 26 70100 0.7 100 5 0.2 Ex. 27 70 100 0.7 100 5 0.2 Ex. 28 70 100 0.7 100 50.1 Ex. 29 70 100 0.7 100 5 0.1 Ex. 30 70 100 0.7 100 5 0.1 Ex. 31 70100 0.7 100 5 0.2 Ex. 32 70 100 0.7 100 5 0.2 Ex. 33 70 100 0.7 100 50.2 Ex. 34 70 100 0.7 100 5 0.1 Ex. 35 70 100 0.7 100 5 0.1 Ex. 36 70100 0.7 100 5 0.1 Ex. 37 70 100 0.7 100 5 0.1 Ex. 38 70 100 0.7 100 50.1 C. Ex. 1 — — — 70 5 0.1 C. Ex. 2 — — — 70 5 0.2 Ex. 39 — — — 100 50.2 Ex. 40 70 100 3.0 100 5 0.2 C. Ex. 3 70 100 0.7 100 5 0.2

[0095] TABLE 6 Test results Scale adhesion prevention (g/m²) number ofdeposi- deposi- deposi- deposi- brightness colored tion tion tion tionindex foreign A B C D (L value) substances Ex. 17 1 2 1 3 73 0 Ex. 18 12 2 3 73 0 Ex. 19 1 3 1 3 73 0 Ex. 20 2 4 3 4 73 0 Ex. 21 3 5 4 6 73 0Ex. 22 3 9 5 11 73 0 Ex. 23 5 10 4 12 73 1 Ex. 24 2 4 2 4 73 0 Ex. 25 13 2 5 73 1 Ex. 26 2 5 4 8 73 0 Ex. 27 4 7 5 10 73 0 Ex. 28 2 4 4 7 73 0Ex. 29 3 4 4 6 73 1 Ex. 30 2 3 3 5 73 0 Ex. 31 1 12 1 14 73 1 Ex. 32 1 33 8 73 1 Ex. 33 2 9 4 12 73 0 Ex. 34 3 5 5 8 73 0 Ex. 35 2 4 2 6 73 0Ex. 36 2 4 3 6 73 0 Ex. 37 1 5 3 5 73 0 Ex. 38 2 7 6 8 73 0 C. Ex. 1 421 8 25 73 24 C. Ex. 2 10 25 11 36 70 25 Ex. 39 5 19 5 35 73 2 Ex. 40 1016 15 41 72 7 C. Ex. 3 9 23 11 29 68 18

1. A scale adhesion preventing agent for use in a polymerizationreactor, comprising, as a main component, a condensate of a phenolrepresented by the following formula (1), a 1-naphthol and an aldehyde,which is soluble in an alkaline aqueous solution:

wherein r¹ and r² are the same or different and each a hydroxyl group,alkyl group having 1 to 8 carbon atoms, halogen atom, hydrogen atom,alkoxycarbonyl group whose alkyl moiety has 1 to 8 carbon atoms orphenyl group, with the proviso that hydrogen atoms are existent at atleast two positions of ortho-positions and para-position with respect tothe hydroxyl group:
 2. The scale adhesion preventing agent of claim 1,wherein the condensate is obtained by carrying out condensation using 1mol of a 1-naphthol, 0.01 to 2 mols of a phenol based on 1 mol of a1-naphthol and 0.2 to 2 mols of an aldehyde based on 1 mol of the totalamount of the 1-naphthol and the phenol.
 3. A process for producing ascale adhesion preventing agent for use in a polymerization reactor,comprising the step of condensing a phenol represented by the followingformula (1), a 1-naphthol and an aldehyde in an aqueous solvent to forma product comprising, as a main component, a condensate soluble in analkaline aqueous solution:

wherein R¹ and R² are the same or different and each a hydroxyl group,alkyl group having 1 to 8 carbon atoms, halogen atom, hydrogen atom,alkoxycarbonyl group whose alkyl moiety has 1 to 8 carbon atoms orphenyl group, with the proviso that hydrogen atoms are existent at atleast two positions of ortho-positions and para-position with respect tothe hydroxyl group.
 4. The process of claim 3, comprising the steps ofmixing a phenol represented by the following formula (1), a 1-nahthol,an aldehyde and a basic catalyst into an aqueous solvent at atemperature of 80° C. or less and raising the temperature to 90 to 150°C. at a rate of 2° C./min or less to carry out a condensation reaction:

wherein R¹ and R² are the same or different and each a hydroxyl group,alkyl group having 1 to 8 carbon atoms, halogen atom, hydrogen atom,alkoxycarbonyl group whose alkyl moiety has 1 to 8 carbon atoms orphenyl group, with the proviso that hydrogen atoms are existent at atleast two positions of ortho-positions and para-position with respect tothe hydroxyl group.
 5. A scale adhesion preventing agent for use in avinyl monomer polymerization reactor, comprising, as a main component, acondensate of catechol, 1-naphthol and at least one aldehyde selectedfrom the group consisting of formaldehyde and acetaldehyde.
 6. A scaleadhesion preventing agent for use in a vinyl chloride polymerizationreactor, comprising, as a main component, a condensate of catechol,1-naphthol and formaldehyde.
 7. A polymerization reactor having a filmof the scale adhesion preventing agent of any one of claims 1, 2, 5 and6 on an inner wall of the polymerization reactor.
 8. A process forproducing a vinyl polymer, comprising polymerizing a vinyl monomer usingthe polymerization reactor of claim 7.